This invention relates to an insertion medical device and, more particularly, to hollow rubber dilators filled with flowable material for treating constricted, internal passageways.
Stenosis, or esophageal stricture, is a narrowing or constricting of the diameter of a patient""s esophagus and prevents the normal peristaltic activities of the esophagus. It may impede the patient""s ability to swallow and/or block access to the digestive tract. Treatment often requires dilation of the esophagus at its junction with the stomach.
As noted in U.S. Pat. No. 5,366,471, there are several esophageal dilators known in the art. One such dilator is a bougie having a hollow, central channel extending the length of the bougie, for insertion of a guide wire previously placed in the patient. This type of dilator is most often used with tight strictures that are 1.2 centimeters, or less, in diameter. Another type of dilator is a wire-guided balloon dilator. The guide wire locates the balloon in the stricture and, thereafter, the balloon is slowly inflated. The balloon dilator is best used in asymmetrical strictures that are 1.2 centimeters, or more, in diameter.
Another type of esophageal dilator is the Mercury-filled rubber bougie. The bougie comprises a rubber sheath filled with Mercury, and having a tapered tip. The bougie is inserted, tip-first, through a patient""s mouth and into the esophagus, applying light pressure to enlarge the diameter of the stricture. The rubber bougie is best used in treating strictures which are symmetrical and more than 1.2 centimeters in diameter. Since most esophageal strictures meet these requirements, the rubber bougie is the most commonly used esophageal dilator.
The Mercury core provides the weight necessary for proper performance of the dilator, and, because Mercury is liquid at ambient and body temperatures, it allows flexing of the dilator.
Ribs can form in the surface of a rubber dilator at the location of a tight bend, and can cause damage to the interior lining of the patient""s esophagus. The Mercury core also prevents ribs from forming in the outer surface of the sheath at the location of a tight bend.
One disadvantage to the use of Mercury as the core of a rubber bougie is that Mercury is toxic to humans. The quantity of Mercury held in a bougie could result in a fatality if it were to escape into the patient. The flowability of liquid Mercury enhances the danger, since even a small crack in the sheath of the bougie could result in leakage of the entire quantity of Mercury leaking out of the bougie and into the patient""s mouth, esophagus or stomach. If Mercury enters the bloodstream, it can cause mercury poisoning. In addition, the physical action of a large quantity of Mercury on the digestive tract can cause severe effects. Thus, there are significant health risks associated with the use of Mercury.
U.S. Pat. No. 5,366,471 (xe2x80x9cthe ""471 patentxe2x80x9d) discloses an esophageal dilator where instead of using Mercury, a solution of Tungsten powder suspended in silicone is used. This invention seeks to achieve the benefits of Mercury but without the health risks. The ""471 patent teaches that the Tungsten powder, if not suspended in silicone, may cake up, or pack together, forming clumps. The ""471 patent teaches that Tungsten powder, if not suspended in silicone, may not have adequate flowability properties and ribs may form in the bougie and this could damage the patient""s esophagus. However, one disadvantage of the suspension of Tungsten in silicone claimed in the ""471 patent is that the silicone fluid has the potential of leakage in the event the bougie is cracked.
What is desired, therefore, is a medical device that is filled with a material that possesses adequate flowability properties such that, when inserted into a constricted, internal passageway, the device does not form ribs and can be easily maneuvered to effect dilation. What is also desired is that the material substantially fill the bougie in order to allow the bougie to be inserted deep into the passageway and still maintain adequate weight for maneuverability and to be free from forming ribs throughout the bougie. What is further desired is a material that would not easily flow from a damaged or cracked bougie into the patient""s body.
Accordingly, it is the object of this invention to provide an apparatus and method for making an insertion medical device.
It is another object to provide an apparatus for dilating internal strictures using a flexible tube of adequate weight and flowability comprising crystalline tungsten powder.
It is another object to provide a bougie comprising crystalline tungsten powder for dilating internal strictures wherein, while maneuvering through narrow and curved passageways, said bougie maintains a smooth, uninterrupted surface free from creases.
It is another object to make an apparatus that provides adequate weight and flowability to facilitate the use of other insertion devices such as feeding tubes and endoscopy instruments.
Yet another object is to provide a method for making a bougie substantially filled with crystalline tungsten powder.
These and other objects of the invention are achieved by an apparatus and method for making an insertion medical device comprising a flexible, silicone rubber tube with a tapered tip; said flexible, silicone rubber tube having an enclosed, hollow space; and crystalline tungsten powder substantially filling said enclosed, hollow space.